Delta 4 Should Be Replaced by New Delta 5

[robert_d]

Should SLS be cancelled, there will be 16 or so RS25D's available. If  not, the production of these engines may be restarted.

I would propose the following:
Close out the Delta 4 but use the 5 meter tooling to build a new Hydrolox booster.

Delta 5.
Build a manrated 5 meter Delta 5 using two RS-25's and three Blue Origin BE-3's for the re-usable first stage. Since the BE-3's are restartable, use them for the boostback/reentry and landing burns. Second stage would be powered by one BE-3 vacuum optimized engine.
Once this booster is in service, end production of the Atlas 5 and move the CST-100 to the new vehicle.
A totally US built vehicle lifting a US built capsule. 

[IanThePineapple]

NASA would likely never combine first stage liquid engines. Interesting thought though.

[Coastal Ron]

Should SLS be cancelled, there will be 16 or so RS25D's available. If  not, the production of these engines may be restarted.

I would propose the following:
Close out the Delta 4 but use the 5 meter tooling to build a new Hydrolox booster.

ULA knows what their options are, and Vulcan is the plan.  Plus, the RS-25 is NASA's problem, not ULA's, and it makes no sense for ULA to commit to spending their own money to bail out NASA.  That makes no sense at all.

[MATTBLAK]

I came up with a similar, 'Rocket Lego' idea in an old thread. If SLS is cancelled but they (NASA, ULA etc) wanted to use the RS-25s up: use the Delta IV corestage powered by a single RS-25 and using 6x or 8x GEM-60 solid strap on boosters - aluminum/lithium structures would also help. The upper stage would be a single engine 5-meter Delta version with an upgrade path to an MB-60 as a more powerful upper stage. With the Delta IV corestage using the more efficient RS-25 as a sustainer engine; this would be a long burner, helping to keep the upper stage fat with propellants for a higher altitude. The increased number of GEM-60 solids on the corestage would compensate somewhat for the lower thrust of the RS-25 over the RS-68.

I wonder what someone like Steve Pietrobon or Ed Kyle could make of the performance figures for such a launcher?

[butters]

Replacing one RS-68 with two RS-25s (plus BE-3s) makes reuse economically mandatory from day one. The RS-25D wasn't exactly easy or cheap to reuse, and the RS-25E wasn't designed to be reusable at all. RS-25 wasn't the solution to economical RLV in the last century, and I can't imagine it's the solution to economical RLV in this century.

Vulcan is a more sensible plan for the Delta 4 tooling, in my opinion. I have trouble seeing how a semi-reusable-at-best Vulcan will compete with New Glenn or SpaceX, but with the engines available to ULA? It's either Vulcan, or a bunch of BE-3s (Delta 11?), or scale up to larger tooling and copy New Glenn.

[ZachS09]

robert_d, what throttle level would the two RS-25 engines be set to during the ascent?

I'm not sure if it's either 104.5% or 109%.

[robert_d]

Replacing one RS-68 with two RS-25s (plus BE-3s) makes reuse economically mandatory from day one. The RS-25D wasn't exactly easy or cheap to reuse, and the RS-25E wasn't designed to be reusable at all. RS-25 wasn't the solution to economical RLV in the last century, and I can't imagine it's the solution to economical RLV in this century.

Vulcan is a more sensible plan for the Delta 4 tooling, in my opinion. I have trouble seeing how a semi-reusable-at-best Vulcan will compete with New Glenn or SpaceX, but with the engines available to ULA? It's either Vulcan, or a bunch of BE-3s (Delta 11?), or scale up to larger tooling and copy New Glenn.

I understood that the last version flown of the RS-25 was good for up to 60 reflights (of shuttle duration or 8.5 minutes) without major overhaul. If that is the case even at 24 million a piece and assuming start/stop is the limiting factor you are talking only 0.8 million in engine cost per flight for Delta5. Say 1.5 million including inspection of all 5 engines.

And you get a man-rated booster, with a big enough 2nd stage to allow consideration of refueling in orbit.

[robert_d]

robert_d, what throttle level would the two RS-25 engines be set to during the ascent?

I'm not sure if it's either 104.5% or 109%.

Probably shuttle level of 104%, as that is likely as high as re-use would allow.

[Space Ghost 1962]

Not everything deserves to be flown. Outside of the common avionics/tanks/stage fabrication/thrust structure, all of which are refined and used on Vulcan, can't think of anything worth reusing.

The plumbing can never be cheap enough. Neither RS-68 nor SSME would be optimal for booster engines. Integration is too difficult, the GSE/pad horrendously expensive to maintain.

If you were to compare flight systems between Atlas V and Delta IV, you'd find Delta shortcomings that Atlas better addresses.

As to US, Centaur delivers most of the performance over the larger DCSS for a fraction of the weight.

So apart from space cadet need to keep flying everything that can fly, can't think of the reason for anything more.

DIVH addresses a narrow need, likely to be surpassed soon. After that, there's just certain legacy need. Which will fade fast.

Delta IV was done in the shadow of the Shuttle, with the understanding that hydrolox was the ideal LRE, and the only better thing would be nuclear. As Tom Mueller/SX has found out, when you do the trades that doesn't always pan out.

Ariane 6 is the next hydrolox LV. Unlike Delta IV (but like Ariane 5), which can launch a useful payload w/o SRMs. Learning from its design, its more of a cost reduced version of its predecessor, including a different way to integrate the vehicle for flight with completely different pad/operations.

So if you were to follow the same formula, a Delta V would have a cost reduced but higher performance engine (how you'd do  that might be a tap-off or double expander), fully integrate the vehicle horizontally, have a clean pad with a TE, and a mobile service structure that vertically integrates the vehicle with payload.

(Likely for competitive reasons, you'd desire a carbon fiber tanks/structures, and horizontal payload integration. If you were to reuse the booster, you'd want to have the engine throttle down like NS and land similarly downrange.)

Might you be able to do this - perhaps. It likely would cost a few billion. But what would you gain?

[ZachS09]

I came up with a similar, 'Rocket Lego' idea in an old thread. If SLS is cancelled but they (NASA, ULA etc) wanted to use the RS-25s up: use the Delta IV corestage powered by a single RS-25 and using 6x or 8x GEM-60 solid strap on boosters - aluminum/lithium structures would also help. The upper stage would be a single engine 5-meter Delta version with an upgrade path to an MB-60 as a more powerful upper stage. With the Delta IV corestage using the more efficient RS-25 as a sustainer engine; this would be a long burner, helping to keep the upper stage fat with propellants for a higher altitude. The increased number of GEM-60 solids on the corestage would compensate somewhat for the lower thrust of the RS-25 over the RS-68.

I wonder what someone like Steve Pietrobon or Ed Kyle could make of the performance figures for such a launcher?

I used http://www.silverbirdastronautics.com/LVperform.html for the performance figures of this Delta V concept. I also used the ULA Launch User's Guide for Delta IV as a reference.

Here's how I did this: I put in the numbers regarding the mass of each stage, typed in the altitude and inclination, calculated the payload weight, and subtracted that total by the mass of the payload attach fitting to get the actual payload weight.

The following performance numbers assume that this launch vehicle is situated at either SLC-37B in Cape Canaveral or SLC-6 in Vandenberg.

For the Delta V with 6 SRBs, GTO (185 by 35,786 at 27 degrees) payload is about 8566 kilograms, LEO (200 by 200 at 28.7 degrees) payload is about 24,581 kilograms, and SSO (600 by 600 at 98 degrees, or 800 by 800 at 98 degrees) payload is between 16,070 and 17,887 kilograms.

For the Delta V with 8 SRBs, GTO (185 by 35,786 at 27 degrees) payload is about 9632 kilograms, LEO (200 by 200 at 28.7 degrees) payload is about 27,099 kilograms, and SSO (600 by 600 at 98 degrees, or 800 by 800 at 98 degrees) payload is between 17,794 and 19,778 kilograms.

In conclusion, both variants of this Delta V concept are heavy-lift launch vehicles because, according to https://www.nasa.gov/pdf/500393main_TA01-LaunchPropulsion-DRAFT-Nov2010-A.pdf, heavy-lift rockets carry between 20,000 and 50,000 kilograms into Low Earth Orbit.

[Zed_Noir]

....

I used http://www.silverbirdastronautics.com/LVperform.html for the performance figures of this Delta V concept. I also used the ULA Launch User's Guide for Delta IV as a reference.

Here's how I did this: I put in the numbers regarding the mass of each stage, typed in the altitude and inclination, calculated the payload weight, and subtracted that total by the mass of the payload attach fitting to get the actual payload weight.

The following performance numbers assume that this launch vehicle is situated at either SLC-37B in Cape Canaveral or SLC-6 in Vandenberg.

For the Delta V with 6 SRBs, GTO (185 by 35,786 at 27 degrees) payload is about 8566 kilograms, LEO (200 by 200 at 28.7 degrees) payload is about 24,581 kilograms, and SSO (600 by 600 at 98 degrees, or 800 by 800 at 98 degrees) payload is between 16,070 and 17,887 kilograms.

For the Delta V with 8 SRBs, GTO (185 by 35,786 at 27 degrees) payload is about 9632 kilograms, LEO (200 by 200 at 28.7 degrees) payload is about 27,099 kilograms, and SSO (600 by 600 at 98 degrees, or 800 by 800 at 98 degrees) payload is between 17,794 and 19,778 kilograms.

In conclusion, both variants of this Delta V concept are heavy-lift launch vehicles because, according to https://www.nasa.gov/pdf/500393main_TA01-LaunchPropulsion-DRAFT-Nov2010-A.pdf, heavy-lift rockets carry between 20,000 and 50,000 kilograms into Low Earth Orbit.

That is for expendable versions of  the OP proposed Delta 5?

Any guesses for a re-usable versions of the Delta 5?
 

[ZachS09]

These performance figures I calculated were based off of MATTBLAK's concept, which is not reusable. robert_d's concept is reusable.

[envy887]

I came up with a similar, 'Rocket Lego' idea in an old thread. If SLS is cancelled but they (NASA, ULA etc) wanted to use the RS-25s up: use the Delta IV corestage powered by a single RS-25 and using 6x or 8x GEM-60 solid strap on boosters - aluminum/lithium structures would also help. The upper stage would be a single engine 5-meter Delta version with an upgrade path to an MB-60 as a more powerful upper stage. With the Delta IV corestage using the more efficient RS-25 as a sustainer engine; this would be a long burner, helping to keep the upper stage fat with propellants for a higher altitude. The increased number of GEM-60 solids on the corestage would compensate somewhat for the lower thrust of the RS-25 over the RS-68.

I wonder what someone like Steve Pietrobon or Ed Kyle could make of the performance figures for such a launcher?

I used http://www.silverbirdastronautics.com/LVperform.html for the performance figures of this Delta V concept. I also used the ULA Launch User's Guide for Delta IV as a reference.

Here's how I did this: I put in the numbers regarding the mass of each stage, typed in the altitude and inclination, calculated the payload weight, and subtracted that total by the mass of the payload attach fitting to get the actual payload weight.

The following performance numbers assume that this launch vehicle is situated at either SLC-37B in Cape Canaveral or SLC-6 in Vandenberg.

For the Delta V with 6 SRBs, GTO (185 by 35,786 at 27 degrees) payload is about 8566 kilograms, LEO (200 by 200 at 28.7 degrees) payload is about 24,581 kilograms, and SSO (600 by 600 at 98 degrees, or 800 by 800 at 98 degrees) payload is between 16,070 and 17,887 kilograms.

For the Delta V with 8 SRBs, GTO (185 by 35,786 at 27 degrees) payload is about 9632 kilograms, LEO (200 by 200 at 28.7 degrees) payload is about 27,099 kilograms, and SSO (600 by 600 at 98 degrees, or 800 by 800 at 98 degrees) payload is between 17,794 and 19,778 kilograms.

In conclusion, both variants of this Delta V concept are heavy-lift launch vehicles because, according to https://www.nasa.gov/pdf/500393main_TA01-LaunchPropulsion-DRAFT-Nov2010-A.pdf, heavy-lift rockets carry between 20,000 and 50,000 kilograms into Low Earth Orbit.

That seems rather high to me. Can you post the numbers you plugged in for LEO, or attach a screencap?

[ZachS09]

DELTA V

Six GEM-60 SRBs

Common Booster Core first stage with one RS-25D engine at 104.5%

5-meter Delta Cryogenic Second Stage with one MB-60 engine

5-meter composite payload fairing



DELTA V+

Eight GEM-60 SRBs

Common Booster Core first stage with one RS-25D engine at 104.5%

5-meter Delta Cryogenic Second Stage with one MB-60 engine

5-meter composite payload fairing



The dry masses of the CBC and DCSS are different because I subtracted the mass of the RS-68 and RL-10 by the dry mass of each stage respectively and to each of those numbers, I added the mass of the RS-25D and MB-60 engines.

I apologize if this does not make sense, but I did try my hardest to explain everything, envy887.

[ZachS09]

Also, per the Delta IV User's Guide, the payload adapter I chose is about 446 kilograms, so once you see the payload mass, subtract that number by 446.

[edkyle99]

A straight up re-engined first stage with two RS-25 engines bumps GTO payload up from 4.2 tonnes (RS-68A) to 6.5 tonnes (GEO - 1800 m/s).  You could also stretch the first stage a bit, thanks to the higher thrust compared to a single RS-68A, and get 7.5 tonnes to GTO.  A nice improvement, but at great cost.

 - Ed Kyle

[envy887]

DELTA V

Six GEM-60 SRBs

Common Booster Core first stage with one RS-25D engine at 104.5%

5-meter Delta Cryogenic Second Stage with one MB-60 engine

5-meter composite payload fairing



DELTA V+

Eight GEM-60 SRBs

Common Booster Core first stage with one RS-25D engine at 104.5%

5-meter Delta Cryogenic Second Stage with one MB-60 engine

5-meter composite payload fairing



The dry masses of the CBC and DCSS are different because I subtracted the mass of the RS-68 and RL-10 by the dry mass of each stage respectively and to each of those numbers, I added the mass of the RS-25D and MB-60 engines.

I apologize if this does not make sense, but I did try my hardest to explain everything, envy887.

No, that makes perfect sense. But check your ISP values. I've found that tool only gives realistic outputs when using the AVERAGE ISP, not the vacuum ISP (despite what the hover hint says). So the GEMs should be around 250, the SSME around 415, and the MB-60 467 seconds.

[ZachS09]

Please forgive me, envy887. I made a typo when inputting the ISP for MB-60. It should have been 466.7 and not 266.9.

When you said, "use the AVERAGE specific impulse," are you referring to the specific impulse at sea level?

[RocketmanUS]

@ robert_d
We already have the Atlas V and the Falcon 9.
Atlas V and Delta IV are expected to be replaced by Vulcan.
We expect to have Falcon heavy and New Glenn.

It would be better to spend the time working on payloads and BLEO missions for these launchers.
So why keep trying to find a replacement for SLS and or reuse of shuttle hardware?
Very true SLS has to go sooner than later. It is holding the U.S. space program back by funding and resources.

[Chasm]

So the goal is to keep flying RS-25 engines?